1. Field of the Invention
The present invention relates to a reflector having asymmetrical concave portions and a liquid crystal display device having the same. More particularly, it relates to a reflector in which a reflection characteristic is prevented from deteriorating even at a large transmissive opening and a liquid crystal display device having the same.
2. Description of the Related Art
In portable electronic devices such as portable phones or portable game devices, a reflection-type liquid crystal display device capable of decreasing the power consumption is provided as a display part, since the lifetime of battery largely affects the convenience of electronic devices. The reflection-type liquid crystal display devices are provided with a reflector for total-reflecting external light incident from a front surface or a reflector for reflecting the external light incident from the front surface and transmitting light emitted from a backlight. As such a reflector, there is known a reflector provided with a plurality of fine concave or convex portions to maximally increase the reflectance of the reflector (for example, see Japanese Unexamined Patent Application Publication No. 11-52110).
Among these reflectors, particularly, the reflector for reflecting the external light and transmitting the light emitted from the backlight is referred to as a transflective reflector. In the transflective reflector, openings for transmitting light emitted from an illumination device, such as a backlight, toward the liquid crystal display panel are formed in a portion of a metal thin film having a plurality of fine concave portions thereon, which are formed by either sandblasting or photolithography or both. Therefore, the liquid crystal display panel can be brightly illuminated by any light source such as the external light or the illuminating device.
However, in the above-mentioned conventional reflector, the shape of each of the concave or convex portions, particularly, the section shape is not controlled by the distribution state of angle of inclination, but the reflection characteristic forms a so-called Gaussian distribution, which is symmetrical with respect to the specular reflection angle in a narrow range. Accordingly, if the openings are formed in the transflective reflector, the reflectance of the wide viewing angle area is significantly deteriorated. Accordingly, there are problems in that the brightness decreases and the image angle becomes narrow, which result in lowering the viewing convenience.